Videocommunicating arrangements generally include a camera for generating video signals, a microphone, sometimes integrated with the camera, a speaker for reproducing sound from a received audio signal, a video display for displaying a scene from a remote location, one or more processors for encoding and decoding video and audio, and a communication interface. In some instances the arrangement includes a speaker and microphone that are separate and not part of an integrated unit.
One problem that arises in videocommunicating applications, and with speakerphones, as well, is the feedback of an audio signal from the speaker into the microphone. With this feedback of an audio signal, a participant hears an echo of his/her voice. Various methods are used to eliminate the echo in such arrangements. One approach to dealing with echo is operating in a half-duplex mode. In half-duplex mode, the arrangement is either transmitting or receiving an audio signal at any given time, but not both transmitting and receiving. Thus, only one person at a time is able to speak and be heard at both ends of the conversation. This may be undesirable because comments and/or utterances by a party may be lost, thereby causing confusion and wasting time.
Another approach for addressing the echo problem is an echo-cancellation circuit coupled to the microphone and speaker. With echo-cancellation, a received audio signal is modeled and thereafter subtracted from the audio generated by the microphone to cancel the echo. However, a problem with echo-cancellation is determining the proper time at which to model the received audio signal.
Therefore, it would be desirable to have a system that addresses the problems described above as well as other problems associated with videocommunicating.